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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.media;
import android.annotation.NonNull;
import android.os.Parcel;
/**
* Class encapsulating subtitle data, as received through the
* {@link MediaPlayer.OnSubtitleDataListener} interface.
* The subtitle data includes:
* <ul>
* <li> the track index</li>
* <li> the start time (in microseconds) of the data</li>
* <li> the duration (in microseconds) of the data</li>
* <li> the actual data.</li>
* </ul>
* The data is stored in a byte-array, and is encoded in one of the supported in-band
* subtitle formats. The subtitle encoding is determined by the MIME type of the
* {@link MediaPlayer.TrackInfo} of the subtitle track, one of
* {@link MediaFormat#MIMETYPE_TEXT_CEA_608}, {@link MediaFormat#MIMETYPE_TEXT_CEA_708},
* {@link MediaFormat#MIMETYPE_TEXT_VTT}.
* <p>
* Here is an example of iterating over the tracks of a {@link MediaPlayer}, and checking which
* encoding is used for the subtitle tracks:
* <p>
* <pre class="prettyprint">
* MediaPlayer mp = new MediaPlayer();
* mp.setDataSource(myContentLocation);
* mp.prepare(); // synchronous prepare, ready to use when method returns
* final TrackInfo[] trackInfos = mp.getTrackInfo();
* for (TrackInfo info : trackInfo) {
* if (info.getTrackType() == TrackInfo.MEDIA_TRACK_TYPE_SUBTITLE) {
* final String mime = info.getFormat().getString(MediaFormat.KEY_MIME);
* if (MediaFormat.MIMETYPE_TEXT_CEA_608.equals(mime) {
* // subtitle encoding is CEA 608
* } else if (MediaFormat.MIMETYPE_TEXT_CEA_708.equals(mime) {
* // subtitle encoding is CEA 708
* } else if (MediaFormat.MIMETYPE_TEXT_VTT.equals(mime) {
* // subtitle encoding is WebVTT
* }
* }
* }
* </pre>
* <p>
* See
* {@link MediaPlayer#setOnSubtitleDataListener(android.media.MediaPlayer.OnSubtitleDataListener, android.os.Handler)}
* to receive subtitle data from a MediaPlayer object.
*
* @see android.media.MediaPlayer
*/
public final class SubtitleData
{
private static final String TAG = "SubtitleData";
private int mTrackIndex;
private long mStartTimeUs;
private long mDurationUs;
private byte[] mData;
/** @hide */
public SubtitleData(Parcel parcel) {
if (!parseParcel(parcel)) {
throw new IllegalArgumentException("parseParcel() fails");
}
}
/**
* Constructor.
*
* @param trackIndex the index of the media player track which contains this subtitle data.
* @param startTimeUs the start time in microsecond for the subtitle data
* @param durationUs the duration in microsecond for the subtitle data
* @param data the data array for the subtitle data. It should not be null.
* No data copying is made.
*/
public SubtitleData(int trackIndex, long startTimeUs, long durationUs, @NonNull byte[] data) {
if (data == null) {
throw new IllegalArgumentException("null data is not allowed");
}
mTrackIndex = trackIndex;
mStartTimeUs = startTimeUs;
mDurationUs = durationUs;
mData = data;
}
/**
* Returns the index of the media player track which contains this subtitle data.
* @return an index in the array returned by {@link MediaPlayer#getTrackInfo()}.
*/
public int getTrackIndex() {
return mTrackIndex;
}
/**
* Returns the media time at which the subtitle should be displayed, expressed in microseconds.
* @return the display start time for the subtitle
*/
public long getStartTimeUs() {
return mStartTimeUs;
}
/**
* Returns the duration in microsecond during which the subtitle should be displayed.
* @return the display duration for the subtitle
*/
public long getDurationUs() {
return mDurationUs;
}
/**
* Returns the encoded data for the subtitle content.
* Encoding format depends on the subtitle type, refer to
* <a href="https://en.wikipedia.org/wiki/CEA-708">CEA 708</a>,
* <a href="https://en.wikipedia.org/wiki/EIA-608">CEA/EIA 608</a> and
* <a href="https://www.w3.org/TR/webvtt1/">WebVTT</a>, defined by the MIME type
* of the subtitle track.
* @return the encoded subtitle data
*/
public @NonNull byte[] getData() {
return mData;
}
private boolean parseParcel(Parcel parcel) {
parcel.setDataPosition(0);
if (parcel.dataAvail() == 0) {
return false;
}
mTrackIndex = parcel.readInt();
mStartTimeUs = parcel.readLong();
mDurationUs = parcel.readLong();
mData = new byte[parcel.readInt()];
parcel.readByteArray(mData);
return true;
}
}
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